Double-clamped bistable buckled beams demonstrate great versatility in various fields such as robotics,energy harvesting,and microelectromechanical system(MEMS).However,their design often requires time-consuming and e...Double-clamped bistable buckled beams demonstrate great versatility in various fields such as robotics,energy harvesting,and microelectromechanical system(MEMS).However,their design often requires time-consuming and expensive computations.In this work,we present a method to easily and rapidly design bistable buckled beams subjected to a transverse point force.Based on the Euler–Bernoulli beam theory,we establish a theoretical model of bistable buckled beams to characterize their snapthrough properties.This model is verified against the results from a finite element analysis(FEA)model,with maximum discrepancy less than 7%.By analyzing and simplifying our theoretical model,we derive explicit analytical expressions for critical behavioral values on the force-displacement curve of the beam.These behavioral values include critical force,critical displacement,and travel,which are generally sufficient for characterizing the snapthrough properties of a bistable buckled beam.Based on these analytical formulas,we investigate the influence of a bistable buckled beam's key design parameters,including its actuation position and precompression,on its critical behavioral values,with our results validated by FEA simulations.Our analytical method enables fast and computationally inexpensive design of bistable buckled beams and can guide the design of complicated systems that incorporate bistable mechanisms.展开更多
The development of machine learning has provided a new perspective for the design of electromagnetic metastructures,particularly in the rapid design of key performance metrics such as effective absorption bandwidth.Tr...The development of machine learning has provided a new perspective for the design of electromagnetic metastructures,particularly in the rapid design of key performance metrics such as effective absorption bandwidth.Traditional methods,grounded in electromagnetic theory and empirical approaches,often lacked sufficient flexibility and adaptability.In this work,three types of machine learning models were developed to establish the relationship between effective absorption bandwidth and structural parameters.The results indicated that the random forest model achieved the most accurate and efficient design for this task.Then,the additive manufacturing optimal metastructure obtained using this approach outperformed existing designs in terms of both effective absorption bandwidth and reflectivity,while also exhibiting superior radar stealth performance and mechanical load-bearing capacity.Furthermore,through interpretable machine learning and data analysis,the intrinsic mechanisms underlying the relationship between effective absorption bandwidth and structural parameters were revealed.Overall,this work introduced a novel approach to metastructure design and enhanced the understanding of the relationship between structural parameters and electromagnetic properties,providing a key foundation for future design.展开更多
Satellite constellation configuration design is a complicated and time-consuming simulation optimization problem. In this paper, a new method called the rapid method for satellite constellation performance calculation...Satellite constellation configuration design is a complicated and time-consuming simulation optimization problem. In this paper, a new method called the rapid method for satellite constellation performance calculation is developed by the Hermite interpolation technique to reduce the computing complication and time. The constellation configuration optimization model is established on the basis of the rapid performance calculation. To reduce the search space and enhance the optimization efficiency, this paper presents a new constellation optimization strategy based on the ordinal optimization （00） theory and expands the algorithm realization for constellation optimization including precise and crude models, ordered performance curves, selection rules and selected subsets. Two experiments about navigation constellation and space based surveillance system （SBSS） are carried out and the analysis of simulation results indicates that the ordinal optimization for satellite constellation configuration design is effective.展开更多
Waverider design based on osculating theory presents two critical issues:robust specification of design curves and accurate solution of the basic flowfield.Although the existing parametric approaches have advanced rap...Waverider design based on osculating theory presents two critical issues:robust specification of design curves and accurate solution of the basic flowfield.Although the existing parametric approaches have advanced rapid configuration generation through geometric parameterization frameworks,they critically neglect the inherent coupling between aerodynamic constraints and geometric design parameters.To overcome this limitation,an Aerodynamics-Informed Parametric(AIP)method is developed by analytically deriving three waverider design curves and integrating them with the second-order curved shock theory.This method enables rapid waverider surface design while accounting for inflow conditions and shock wave geometry.Three typical waveriders,each featuring distinct combinations of design curves as inputs,are constructed and evaluated through inviscid and viscous numerical simulations to validate the applicability and accuracy of the AIP method.The results indicate that waveriders derived using the AIP method successfully reproduce the preassigned shock waves and original flowfields.Compared to traditional waverider design techniques based on the method of characteristics,the AIP method reduces computation time by approximately 94%,while maintaining errors in the inviscid lift-to-drag ratio,viscous lift-to-drag ratio,and volumetric efficiency below 0.1%,4.0%,and 0.1%,respectively.Additionally,a specially designed model is fabricated for the wind-tunnel tests to analyze the hypersonic aerodynamic performance of the waverider.Both numerical and experimental results confirm the feasibility of the AIP method,making it a promising candidate for waverider design and optimization.展开更多
基金financial support from the National Science Foundation of the United State (Grants 1752575 and 1644579)
文摘Double-clamped bistable buckled beams demonstrate great versatility in various fields such as robotics,energy harvesting,and microelectromechanical system(MEMS).However,their design often requires time-consuming and expensive computations.In this work,we present a method to easily and rapidly design bistable buckled beams subjected to a transverse point force.Based on the Euler–Bernoulli beam theory,we establish a theoretical model of bistable buckled beams to characterize their snapthrough properties.This model is verified against the results from a finite element analysis(FEA)model,with maximum discrepancy less than 7%.By analyzing and simplifying our theoretical model,we derive explicit analytical expressions for critical behavioral values on the force-displacement curve of the beam.These behavioral values include critical force,critical displacement,and travel,which are generally sufficient for characterizing the snapthrough properties of a bistable buckled beam.Based on these analytical formulas,we investigate the influence of a bistable buckled beam's key design parameters,including its actuation position and precompression,on its critical behavioral values,with our results validated by FEA simulations.Our analytical method enables fast and computationally inexpensive design of bistable buckled beams and can guide the design of complicated systems that incorporate bistable mechanisms.
基金financially supported by the Key Research and Development Program of the Ministry of Science and Technology under No.2022YFB3806104.
文摘The development of machine learning has provided a new perspective for the design of electromagnetic metastructures,particularly in the rapid design of key performance metrics such as effective absorption bandwidth.Traditional methods,grounded in electromagnetic theory and empirical approaches,often lacked sufficient flexibility and adaptability.In this work,three types of machine learning models were developed to establish the relationship between effective absorption bandwidth and structural parameters.The results indicated that the random forest model achieved the most accurate and efficient design for this task.Then,the additive manufacturing optimal metastructure obtained using this approach outperformed existing designs in terms of both effective absorption bandwidth and reflectivity,while also exhibiting superior radar stealth performance and mechanical load-bearing capacity.Furthermore,through interpretable machine learning and data analysis,the intrinsic mechanisms underlying the relationship between effective absorption bandwidth and structural parameters were revealed.Overall,this work introduced a novel approach to metastructure design and enhanced the understanding of the relationship between structural parameters and electromagnetic properties,providing a key foundation for future design.
文摘Satellite constellation configuration design is a complicated and time-consuming simulation optimization problem. In this paper, a new method called the rapid method for satellite constellation performance calculation is developed by the Hermite interpolation technique to reduce the computing complication and time. The constellation configuration optimization model is established on the basis of the rapid performance calculation. To reduce the search space and enhance the optimization efficiency, this paper presents a new constellation optimization strategy based on the ordinal optimization （00） theory and expands the algorithm realization for constellation optimization including precise and crude models, ordered performance curves, selection rules and selected subsets. Two experiments about navigation constellation and space based surveillance system （SBSS） are carried out and the analysis of simulation results indicates that the ordinal optimization for satellite constellation configuration design is effective.
基金supported by the National Natural Science Foundation of China(Nos.U21B6003,U20A2069,and 12202372)the China Postdoctoral Science Foundation(No.2022M712653)。
文摘Waverider design based on osculating theory presents two critical issues:robust specification of design curves and accurate solution of the basic flowfield.Although the existing parametric approaches have advanced rapid configuration generation through geometric parameterization frameworks,they critically neglect the inherent coupling between aerodynamic constraints and geometric design parameters.To overcome this limitation,an Aerodynamics-Informed Parametric(AIP)method is developed by analytically deriving three waverider design curves and integrating them with the second-order curved shock theory.This method enables rapid waverider surface design while accounting for inflow conditions and shock wave geometry.Three typical waveriders,each featuring distinct combinations of design curves as inputs,are constructed and evaluated through inviscid and viscous numerical simulations to validate the applicability and accuracy of the AIP method.The results indicate that waveriders derived using the AIP method successfully reproduce the preassigned shock waves and original flowfields.Compared to traditional waverider design techniques based on the method of characteristics,the AIP method reduces computation time by approximately 94%,while maintaining errors in the inviscid lift-to-drag ratio,viscous lift-to-drag ratio,and volumetric efficiency below 0.1%,4.0%,and 0.1%,respectively.Additionally,a specially designed model is fabricated for the wind-tunnel tests to analyze the hypersonic aerodynamic performance of the waverider.Both numerical and experimental results confirm the feasibility of the AIP method,making it a promising candidate for waverider design and optimization.
